As it will violate heisenberg uncertainity principle as well as quantum statistics will not permit it. But dont know proper reasons for it.
The term nucleon signifies any particle that is present inside the nucleus of an atom. We know that the nucleus of any atom contains only two particles which are proton and neutron whereas electron are present outside the nucleus revolving around it. Hence, electron is not a nucleon.
Electrons farthest from nucleus are valence electrons. They are present in outermost orbit.
Protons and neutrons are present in the nucleus. Electrons are present in orbits of an atom. Where as proton are located at centre of the nucleus.
Though the electron itself is not present in the nucleus of an atom, the elementary particles that make up the electron are present inside the neutron. In other words, a neutron is made up of an electron and a proton. How do we know this? Because when a neutron decays, it slowly decays into a proton and an electron. It's a cycle.
While it is useful to visualize an Electron orbiting an atomic nucleus like a moon orbiting a planet. It is more realistic to think of the Electron as a standing wave (with a fixed number of wave crests and troughs) surrounding the nucleus. The electromagnetic force holds the Electron and nucleus together. The Electron holds a negative electrical charge and the nucleus a positive electrical charge and the two attract one another. Therefore for each positive charge present in the atomic nucleus (the Protons) there must be a balancing negative charge (the Electrons) present round the atom.
Valence electrons are present in outermost shell. They are at far distance from nucleus.
In general, the nucleus and the electron cloud are the two distinct features of the volume of the atom. The nucleus is home to the proton(s) and whatever neutrons are present, and the electron cloud is where the electrons all hang out. The nucleus, with its protons and neutrons, has most of an atom's mass concentrated there. The electrons are relatively far away, and the orbits they describe give the atom its "shape" by defining its volume in space.
The farther an electron is from the nucleus, the greater its energy.
nucleus is in the middle and the electron cloud is around it
Electron in an atom is represented by electron cloud around the nucleus
There is no exact location of the electron. The electron is outside the nucleus orbiting the center of the atom. You can't see it because it rotates so fast and is so small. So we can't indicate the exact location of the electron.
An electron in a 2s orbital is on average closer to the nucleus.